Uncertainty evaluation for the spectroradiometric measurement of the averaged light-emitting diode intensity

Seongchong Park, Dong-Hoon Lee, Yong-Wan Kim, and Seung-Nam Park

Seongchong Park,1 Dong-Hoon Lee,1 Yong-Wan Kim,1 and Seung-Nam Park1

1The authors are with the Division of Physical Metrology, Korea Research Institute of Standards and Science,
Doryong-dong 1, Yuseong-gu, Daejeon, South Korea. S. Park's e-mail address is spark@kriss.re.kr.

Abstract

An uncertainty evaluation is presented for the spectroradiometric measurement of the averaged LED intensity (ALI), which is a standardized photometric quantity of LEDs introduced by the Commission Internationale de l'Éclairage.
Using a spectral irradiance standard lamp as a calibration source for the spectroradiometer, 12 uncertainty components are sorted out and their propagation formulated with correlations between the components taken into account. The procedure of uncertainty evaluation is demonstrated for four LED samples of different colors; red, green, blue, and white. The relative uncertainties of the ALI of the test samples are determined to be in a range from 4.1% to 5.5%
(k=2),
but most of their dominant uncertainty components turn out to be systematic and correlated. In conclusion, correlations between the uncertainty components critically affect the overall uncertainty of the LED measurement using a spectroradiometer.

Calibration result of the wavelength scale of the spectroradiometer using a set of wavelength standard lamps: (a) measured data pairs of the reference wavelengths (cross symbols) and the wavelength calibration curve (line) obtained by third-order polynomial fit, (b) standard uncertainties, and (c) correlation coefficients of the wavelength calibration curve.